DE 199 22 850 discloses an apparatus for producing fibre composite mouldings. The apparatus includes a mould part, where the channels extend in the longitudinal direction of the apparatus below the moulding surface, and where the channels are connected to said surface through bores or longitudinal slots. A plurality of valve members communicating with a vacuum source and a resin source, respectively, is placed at each end of the channels. Every second channel communicates with the vacuum source, and every second channel communicates with the resin source, and by time varying the setting of the valve members the flow front of the resin can be controlled during the impregnation process.
EP-A-1555104, which is equivalent to WO 2004/033176, describes a method of resin transfer moulding, wherein a fibre material is placed in a mould, where a first distribution medium for distribution of polymer is placed on a first surface of the fibre material, and where a second distribution medium is placed on the other surface of the fibre material. The first distribution medium exhibits a flow resistance, which is lower than that of the second distribution medium. During an impregnation process, air is evacuated through the second distribution medium via vacuum channels, while liquid polymer is supplied to the first distribution medium. According to a particular embodiment (shown in FIG. 4) the mould is first evacuated by use of vacuum channels, after which polymer via a number of inlet channels is supplied to the bottom of the fibre material. Since the fibre material can be relatively thick, it can be problematic to supply polymer to the top of the fibre material. Therefore, one of the vacuum channels can at the end of the impregnation process be connected to a polymer source by closing a first valve and opening a second valve, thereby supplying polymer to the top of the fibre material via the one vacuum channel. Thereby, it is possible to supply polymer to the top of the fibre material. Additionally, air pockets at the top of the fibre material can be moved towards the other vacuum channel.